The present invention relates to a device for separating large images captured by data acquisition into multiple sub-images and/or for combining them into larger images.
A Numerous applications currently require ever higher signal processing speeds. In particular, high-speed signal processing of very large video images as well as the transmission and storage of such images are proving to be problematic. High-resolution video images of this type can include HDTV images, scanned images, medical images, satellite images, etc. High-speed and, in particular, digital storage systems, such as HDTV recorders, which are used to store high-resolution video images or image sequences, are extremely expensive so that many applications are rejected because of the price.
In addition, the demands placed on the necessary bandwidths are often difficult to meet when processing high-resolution video images in real time, i.e., keeping pace with the desired frame rate. This is true, for example, in the case of scaling, filtering, and data compression.
To solve the problems described above, it is possible to digitize high resolution images and separate them into a number of sub-images. However, it has been shown that separating the images geometrically produces a significant decrease in quality in the area at the edges of the sub-images.
A The object of the present invention is to provide a method as well as a device which can be used to separate high-resolution images into sub-images using a separator and/or to combine corresponding sub-images into a high-resolution image using a combiner, at the same time maintaining a high to maximum image quality, i.e., in particular without any loss in quality.
A significant improvement in image quality can be achieved using a comparatively simple arrangement.
Quite surprisingly, a significant improvement in image quality can be achieved in the applications under discussion using comparatively simple means.
According to the present invention, it has been shown that artifacts are produced when separating and processing image data into sub-image data and when recombining sub-images to create an overall image. These artifacts occur when filtering the image data, which is usually necessary.
According to the present invention, the video data is now separated in a way that shifts the artifacts influencing image quality out of the critical data area so that this image data negatively affected by artifacts can be omitted when recombining the data to form an overall image, i.e., the negatively affected image data can no longer disturb the image following recombination.
In another embodiment of the present invention, the sub-images can be shifted when they are combined, thus counteracting the formation of artifacts and, in particular, thereby producing certain intentional image effects. This can be done, in particular, to adapt the images to different displays.
According to another embodiment of the present invention, a standard conversion operation is carried out at the same time that the sub-images are combined into a high-resolution image, allowing the timing and format of the output image to deviate from the timing and format of the input image.
It is possible, according to the present invention, to analogously set a delay factor during the band-limiting filtering step. In the case of YUV (4:2:2) representation processing, this makes it possible to set the differences between the delay times on the Y and UV channels so that they correspond to exactly one multiple of the clock frequency and so that they can be equalized digitally.
The present invention can be used for HDTV images as well as for computer graphics or other high-reasolution standards.